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<html>
	<head>
		<meta  charset="UTF-8">
		<title>57</title>
	</head>
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var _hmt = _hmt || [];
(function() {
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  hm.src = "https://hm.baidu.com/hm.js?04e828ac441acffeb4a6bc5698f79d55";
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		<script>
		function 闰年(年份){
		var 双闰年=(年份%4==0);
		双闰年=双闰年&&(年份%100==0);
		双闰年=双闰年&&(年份%400==0);
		return 双闰年;
		}
		alert(闰年(1900));
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